Tachometer drive connection.



J. BERG. TACHOMETER DRIVE CONNECTION.

APPLICATION FILED DEC-22. l9]?- Patented Apr. 1,1919,

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I JOSEPH BERG, OF CHICAGO, ILLINOIS, ASSIGNOR TO STEWART-WARNER SPEEDOMETEB CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF VIRGINIA,

TACHOMETER DRIVE CONNECTION.

Specification of Letters Patent.

Patented Apr. 1 19.19.

Application filed December 22, 1917. Serial No. 208,420.

tion, of which the following is a specification, reference being had to the accompanying drawing, forming a part thereof.

The purpose of this invention is to provide a connection between the drive shaft and the driven shaft of a tachometer, so arranged that when the instrument itself is mounted fixedly, the drive shaft may be arranged to extend from the instrument at any desired angle in a given plane, such plane being usually substantially wrtical. The invention consists in the combination and arrangement of the cooperating elements as hereinafter described and shown in the drawings and as indicated in the claim.

In the drawings:

Figure 1 is a side elevation of a tachometer and a portion of its drive shaft presenting an exterior view of a connection embodying this invention.

Fig. 2 is a' vertical section, taken as indicated at line 2-2, on Fig. 1.

Fig. 3 is a detail section taken as indicated at line 33 on Fig. 2.

In designing tachometers for use on aeroplanes as at present constructed, it is found that although the instrument board carrying, the instrument itself is located quite close to the engine, the design of various machines and engines diifers to such an extent that to avoid a multiplicity of constructions in the tachometers themselves, the driveshaft connection must be such that it can extend in any one of several directions from the instrument for connection with the rotary element of the en ine from which the speed is to be derived or causing speed indication b the tachometer. And it is also desirable t at the connection between the instrument and the said rotary partbe by means of a flexible shaft, since the vibration incident to operation of an aeroplane, and the deflection of various parts of its frame render the use of rigid shafts impracticable.

In the present design, therefore, the body of the instrument housed in the casing 1,

includes the driven shaft, 2, carrying at its inner end the magnet, 3, whose function in a tachometer is already well understood; and said shaft, 2, is journaled in ball bearings, 4 and 5, carried in a threaded sleeve, 6, screwed into a central aperture in the back of the case, 1, and secured in such position by a lock nut, 7. At its outer end, the driven shaft carries a spiral gear, 8, and the terminal section, 9, of the flexible drive shaft, housed in the flexible casing, 10, is

indicated in Fig. 2 as a spiral gear, 11, designed to mesh with the gear, 8, for transmitt ng motion to the shaft, 2. Thus it becomes possible for the shaft terminal,-9, to

be rotatively adjusted through any angle in its plane perpendicular to the axis of shaft, 2, without disturbing the relation of the gears 8 and 11.

For housing the shaft terminal, 9, and gear, 11, and maintaining the latter in proper relation to the gear, 8, there is provlded a housing, 12, formed with a split cylindrical portion, 13, provided with a clamp bolt, 14, by which it is sezured on the" protruding end of the bearing tube, 6, and is thus frictionally held against rotation at any adjusted position thereon. A skirt, 15, extending forwardly from the part, 13, serves to inclose and protect the lock nut, 7 by which the tube, 6, is retained in the casing, 1.

The transversely extending cylindrical chamber, 16, communicates with the rear end of the housing, 12, for accommodating the shaft, 9, and its gear, 11, being fitted, as shown in Fig. 2, with a plain bearing bushing, 17, for said shaft, 9, locked in position by a keypin, 18. The outer end of the bushing, 17 is threaded, and the coupling sleeve, 19, of the flexible shaft casing, 10, is screwed onto the thread for joining said casing, 10, with the housing, 12. Preferably a grease cup, 20, is mounted to feed directly to the gears, 8 and 11, as indicated in Fig. 2.

I claim: I

In combination with a tachometer including a casing and a rotary shaft journaled therein, a drive shaft approaching the other shaft transversely, gears operatlvely connecting the two shafts, a tube projecting from said casing and serving to journal the said rotary shaft, and a housing for said gears including a sleeve fitting snugly over ciated ther'ewi and a second sleeve extending of the first and rigidly assoth for journaling the end portion of the drive shaft and its gear,

5 whereby said h be rotatively ad]usted ab tachometer sh aft by turning of the ousing and drive shaft may out the axis of the sleeve upon the tube of the casing, an means for securing said sleeve to said tul at any chosen position of such adjustment.

In testimony whereof, I have hereunto s my hand at Chicago, Illinois, this 30th d:

of November, 1917.

JOSEPH BERG. 

